Vehicle framing system for plurality of vehicle body styles

ABSTRACT

An apparatus and method for randomly interchanging up to four pairs of side framing gates at a framing station of a vehicle assembly line while maintaining a predetermined build cycle time interval of the assembly line. The system employs first and second carousels positioned on opposite sides of the assembly line upstream of the framing station and third and fourth carousels positioned on opposite sides of the production line downstream of the framing station. The system further includes a first linear track structure extending from the first carousel to a first side of the framing station, a second linear track structure extending from the second carousel to a second, opposite side of the framing station, a third linear track structure extending from the third carousel to the first side of the framing station, a third linear track structure extending from the third carousel to the first side of the framing station, and a fourth linear track structure extending from the fourth carousel to the second side of the framing station. The carousel includes at least two sides, possibly three sides, four sides or more, each side capable of receiving a framing gate. The framing gates positioned at the framing station are randomly interchanged by a combination of rotary movements of the carousels and linear movements of framing gates along the linear track structures.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation of U.S. application serial No.60/370,891 filed on Apr. 8, 2002, which is incorporated by referenceherein in its entirety.

FIELD OF THE INVENTION

[0002] The present invention relates to an assembly line framing systemfor clamping and thereafter welding a loosely assembled motor vehiclebody, a framing system that accurately positions and locatespredetermined areas of a loosely assembled motor vehicle body foraccurately clamping and welding the vehicle body together with a highdegree of repeatability between consecutive vehicle bodies on theassembly line, and more particularly a framing system especially adaptedto weld a plurality of different predetermined vehicle body styleswithout interrupting the predetermined build cycle time interval of theassembly line.

BACKGROUND OF THE INVENTION

[0003] The construction of a unitized vehicle body commences with theformation of individual major body panels by stamping the panels fromsheet metal blanks. Typically, these major panels include a floor panel,right and left body side panels, a fire wall and either a roof panel ortransversely extending inner members to which a roof panel issubsequently mounted. After the individual panels are stamped, somepreliminary assembly operations can then be performed on the individualpanels such as for example adding door hinge and latch hardware to bodyside panels at appropriate locations proximate the door openig, addingseat mounting brackets and reinforcements to the floor panels, etc.

[0004] Next a set of panels that together constitute a sub-assembly ofthe finished vehicle body is loosely assembled together. This initialloose assembly of panels frequently is accomplished by a “toy tab”arrangement in which one or more panels is formed with a tab whichprojects from an edge and which is received in a slot in an adjacentpanel. This technique interlocks the panels and frame members to eachother to form a preliminary loosely assembled vehicle body wherein thepanels and frame members will not separate from each other but thepanels and frame members can tilt or move relative to one another. Thisinitial loosely assembled subassembly is then moved along the assemblyline to a framing station where the various panels and frames are weldedto each other to form a rigid permanently assembled vehicle body.

[0005] The welding operation step at the framing station is one of themost important steps in the assembly of the vehicle body because itestablishes the final welded alignment of the various panels and headersrelative to each other which is essential to subsequent assemblyoperations performed on the subassembly. During the welding operation itis critical that the various panels and headers be precisely andaccurately located and aligned relative to one another and be heldfixedly in the desired position. The positioning of the various panelsand header members during the welding operation typically isaccomplished by a pair of side framing gates which are positioned onopposite sides of the assembly line and which carry a plurality ofindividual clamps arranged thereon to clamp the various body componentsin desired positions.

[0006] It is desirable to perform as many welding operations as possibleat the initial framing station since the relative positioning of thevarious panels and headers is critical to the ability to preciselyrelocate and reclamp the vehicle body at subsequent stations along theassembly line. Due to variations between assembly stations and variationin movement of the various panels and headers it is impossible tosubsequently relocate and reclamp the vehicle body without inadvertentlystacking up tolerances or creating variances between the relativepositioning of various panels and headers. Therefore it is desirable toframe as much of the vehicle body as possible at the same framingstation so that a maximum number of welding operations can be performedon the vehicle body without having to subsequently reclamp and relocatethe vehicle body since reclamping and relocating can increase thetolerances between the relative positions of the various panels andheaders of the vehicle body and decrease the repeatability betweenconsecutive vehicle bodies in the production line.

[0007] It is common practice in the present automotive industry for oneparticular car model to be offered in several different body styles.Accommodating each body style requires clamping and welding differentbody locations as well as gaining access to different body areas so thatthe clamping and welding apparatus can be properly positioned whileextending through the framing gates. To avoid having to provide separateassembly lines and framing stations for the different body styles of aparticular car model, it is desirable to provide a single framingstation that can be adapted to accommodate a plurality of different bodystyles in a quick and efficient manner while insuring the accuracy andrepeatability that are required of the welding operation.

SUMMARY OF THE INVENTION

[0008] The present invention provides a framing system that accuratelyand efficiently clamps and welds a loosely assembled vehicle body with ahigh degree of repeatability between consecutive vehicle bodies in aproduction line while also being able to adapt to a plurality ofdifferent loosely assembled body components, corresponding to differentvehicle body styles, in a quick and efficient manner. Specifically, thepresent invention provides a framing system wherein a plurality ofvehicle body styles can be interchangeably accommodated at a singleframing station without interrupting the predetermined build cycle timeinterval of the assembly line. More specifically, the present inventionprovides a framing station wherein four different body styles can beinterchangeably accommodated at a single framing station withoutinterrupting the predetermined build cycle time interval of the assemblyline.

[0009] The body framing system of the invention is intended for use witha vehicle assembly line in which loosely preassembled vehicle bodies aremoved incrementally along a single assembly line from station tostation, successive loosely preassembled vehicle bodies arrive at aframing station along the production line at predetermined build cycletime intervals, and each loosely preassembled vehicle body arriving atthe framing station is welded to form a rigid vehicle body. According tothe invention, the body framing system includes the framing station, aplurality of more than three pairs of opposed side framing gates forpositioning at opposite sides of the framing station for use in weldinga respective plurality of more than three vehicle body styles to allowthe random production of the plurality of more than three vehicle bodystyles on the single assembly line, and a transfer apparatus assemblyoperative to randomly exchange any of the plurality of pairs of sideframing gates positioned at the framing station with any other of theplurality of pairs of side framing gates within the predetermined buildcycle time interval. This arrangement allows the random productioninterchange of the more than three vehicle body styles on the singleassembly line while maintaining the predetermined build cycle timeinterval.

[0010] According to the present invention, the transfer apparatusassembly includes a rotary transfer apparatus coacting with a lineartransfer apparatus. This coacting arrangement facilitates the randominterchange of the more than three pairs of opposed side framing gatesat the framing station. According to the present invention, the rotarytransfer apparatus delivers framing gates to the linear transferapparatus for delivery to the framing station. This specific rotary andlinear coaction further facilitates the random interchange of theframing gates at the framing station. According to the presentinvention, the rotary transfer apparatus includes first and secondcarousels positioned on opposite sides of the assembly line upstream ofthe framing station and third and fourth carousels positioned onopposite sides of the assembly line downstream of the framing station.This arrangement allows the movement of framing gates into the framingstation from positions both upstream and downstream of the framingstation.

[0011] According to the present invention, the linear transfer apparatusincludes a first linear track system extending from the first carouselto a first side of the framing station, a second linear track structureextending from the second carousel to a second opposite side of theframing station, a third linear track structure extending from the thirdcarousel to the first side of a framing station, and a fourth lineartrack structure extending from the fourth carousel to the secondopposite side of the framing station. This arrangement facilitates themovement of the framing gates to the framing station from positionsupstream and downstream of the framing station.

[0012] According to the present invention, each carousel has aconfiguration including at least two sides, each side capable ofreceiving a framing gate. This arrangement allows the storage and randomdelivery of four pairs of framing gates representing four vehicle bodystyles to the framing station. In the illustrated embodiment of theinvention, each carousel has three sides, wherein with the first pair offraming gates positionable on opposite sides of the framing station, thesecond pair of framing gates positionable on respective first sides ofthe first and second carousels, the third pair of framing gatespositionable on respective second sides of the first and secondcarousels, and the fourth pair of framing gates positionable onrespective first sides of the third and fourth carousels, all of thepairs of framing gates can be randomly interchanged by at least one oflinear gate movements along the linear track structures, rotarymovements of the carousels, and a combination of rotary movements of thecarousels and linear gate movements along the linear track structures.

[0013] According to the present invention, the framing station caninclude a base structure, a first pair of spaced pillars mounted on thebase structure on the first side of the framing station, and a secondpair of spaced pillars mounted on the base structure on the second sideof the framing station, the first and second pairs of pillars moveableon the base structure between outboard positions spaced outwardly fromthe assembly line and inboard positions proximate the assembly line, thefirst pair of pillars in its outboard position linearly aligned with thefirst and third linear track structures, and the second pair of pillarsin its outboard position linearly aligned with the second and fourthlinear track structures. This arrangement allows the framing gates to bedelivered to the respective pillar pairs along the respective lineartrack structures with the pillar pairs in the outboard positions,thereafter the pillar pairs can be moved to the inboard positions toposition the framing gates proximate the assembly line where the framinggates can clampingly engage the loosely preassembled bodies preparatoryto the welding operation.

[0014] The present invention can also include a carousel for use indelivering framing gates to a framing station on a vehicle body assemblyline. According to the present invention, the carousel can include abase structure positioned proximate the assembly line and having asupport surface and a central pivot shaft upstanding from the supportsurface, a carousel body supported on the support surface, mounted onthe pivot shaft for rotary movement about the axis of the pivot shaft,and defining a plurality of sides each adapted to receive a framinggate, means operative for generating an air cushion between the supportsurface and an underface of the carousel body to lift the carousel bodyoff of the support surface, and means operative for applying a turningforce to the lifted body. This arrangement allows the carousel body tobe readily rotated about the pivot axis to bring successive sides of thecarousel body into a position proximate the assembly line to facilitatedelivery of the framing gates to the framing station.

[0015] According to the present invention, the operative air cushiongenerating means can include a plurality of air bags positioned on theunderface of the carousel body, each air cushion including a pluralityof apertures in confronting relation to the support surface. With thisarrangement, pressurized air delivered to the airbags can inflate thebags to raise the carousel body off from the support surface and airescaping from the airbags through the apertures can generate an aircushion between the airbags and the support surface to facilitateselective rotation of the carousel.

[0016] According to the present invention, the carousel is intended foruse with a linear track structure having one end positioned proximatethe framing station and a free end, each side of the carousel bodyincluding a carousel track structure for supporting a respective framinggate and configured to be aligned with the free end of the linear trackstructure as the respective side of the carousel body is moved into aposition proximate the assembly line. With this arrangement, the framinggate can be readily slid off from the carousel track structure and ontothe linear track structure for deliver to the framing station.

[0017] The present invention can also include a transfer apparatus foruse in delivering framing gates to a framing station on a vehicle bodyassembly line. According to the present invention, the transferapparatus includes a linear track structure having one end positionedproximate the framing station and a free end, a carousel positionedproximate the assembly line, defining a plurality of sides each adaptedto receive a framing gate, and mounted for rotation about a central axisto bring successive sides of the carousel into a position proximate thefree end of the track structure and in linear alignment with the trackstructure, and a transfer device operative to move a gate positioned ona side of the carousel in alignment with the track structure from thecarousel side, onto the track structure, and along the track structureto the framing station. This arrangement facilitates the transfer of aframing gate from the carousel to the framing station. According to thepresent invention, the transfer device includes a trolley operative toengage a gate and move the gate along the track structure to the framingstation. This arrangement further facilitates the movement of the gatefrom the carousel to the framing station. According to the presentinvention, each side of the carousel includes a carousel track structurefor supporting a framing gate positioned on the respective side of thecarousel and configured to be aligned with the free end of a lineartrack structure as the respective side of the carousel is moved into aposition proximate the free end of the linear track structure. Thisarrangement further facilitates the ready transfer of the framing gatefrom the carousel to the framing station.

[0018] According to the present invention, the transfer apparatus caninclude a first latch device for latching a framing gate to a respectiveside of the carousel, a base structure supporting the carousel, a secondlatch device for latching the carousel to the base structure, and alatch control device operative in response to arrival of a carousel sideat a position proximate the free end of the linear track structure toactuate the second latch device to latch the carousel to the basestructure and release the first latch device to release the framing gatefrom the carousel and allow the trolley to move the released framinggate along the linear track structure to the framing station. Thisarrangement further facilitates the ready transfer of the framing gatefrom the carousel to the framing station. According to the presentinvention, the transfer apparatus can include a third latch device tolatch the trolley to a framing gate, the third latch device is actuatedprior to release of the first latch device and following engagement ofthe second latch device, and the first latch device is releasedfollowing engagement of the third latch device. This arrangement allowsthe trolley to move the released framing gate to the framing station.According to the present invention, the base structure defines a supportsurface, the transfer apparatus can include cushion means operative forgenerating an air cushion between the support surface and an underfaceof the carousel to lift the carousel off of the support surface, andturning means operative for applying a turning force to the liftedcarousel to rotate the carousel about the central axis to bringsuccessive sides of the carousel into position proximate the free end ofthe track structure and in linear alignment with the track structure,and the second latch device is released following actuation of thecushion means, thereafter the turning means is actuated to bring arespective side of the carousel carrying a respective framing gate intoalignment with the linear track structure, thereafter the second linearlatch device is actuated to latch the carousel to the base structure,thereafter the third latch device is actuated to latch the trolley tothe respective framing gate, thereafter the first latch device isreleased to release the respective framing gate from the carousel,thereafter the trolley is actuated to move the respective framing gateto the framing station. This arrangement allows the smooth, rapid andprecise delivery of framing gates from the carousel to the framingstation.

[0019] The present invention further includes a method for moving pairsof framing gates to a framing station on a motor vehicle assembly linewhere loosely preassembled vehicle bodies are clamped by the framinggate pairs while the bodies are welded to form a rigid vehicle body. Themethod can include the steps of providing a pair of carousels, eachcarousel having a plurality of substantially flat sides, positioning thecarousels along and on opposite sides of the assembly line in spacedrelation to the framing station, mounting the carousels for rotation tobring successive sides of the carousels into a discharge positionproximate and substantially parallel to the assembly line, positioning apair of framing gates on one side of the respective pair of carousels,rotating the carousels to bring the one carousel sides into thedischarge position, discharging the framing gates from the carousels,and sliding the framing gates along the assembly line to opposite sidesof the framing station. This methodology facilitates the delivery of aplurality of pairs of framing gates, corresponding to a plurality ofvehicle body styles, to the framing station. According to the presentinvention, the method can include the further steps of providing lineartrack structures extending from each carousel to the framing station,and the sliding step of the discharged framing gates along the assemblylines to the framing station can include the step of sliding thedischarged framing gates along the linear track structures to theframing stations. This methodology further facilitates the delivery ofthe discharged framing gates to the framing station.

[0020] According to the present invention, the rotating step of thecarousels can include the steps of generating an air cushion between anunderface of the carousels and a support surface to lift the carouselsoff of the support surface, and thereafter applying a turning force tothe lifted carousels. This arrangement allows the carousel rotation tobe performed in a minimum amount of time, thereby minimizing the timerequired to perform the total framing gate interchange at the framingstation.

[0021] According to the present invention, the pair of carousels caninclude a first pair of carousels positioned upstream on the assemblyline from the framing station, the pair of framing gates can include afirst pair of framing gates, the sliding step of the discharged framinggates along the assembly line to opposite sides of the framing stationcan include the steps of sliding the framing gates downstream to theframing station, providing a second pair of carousels each having aplurality of substantially flat sides, positioning the second pair ofcarousels along and on opposite sides on the assembly line downstream ofthe framing station, mounting the second pair of carousels for rotationto bring successive sides of the second pair of carousels into adischarge position proximate and substantially parallel to the assemblyline, positioning a second pair of framing gates on one side of therespective second pair of carousels, rotating the second pair ofcarousels to bring the one sides of the second pair of carousels intothe discharge position, discharging the second pair of framing gatesfrom the second pair of carousels, and sliding the discharged secondpair of framing gates upstream to the framing station. This methodologyallows the precise and rapid delivery of framing gates to the framingstation from locations both upstream and downstream of the framingstation.

[0022] According to the present invention, the method can include thesteps of providing a third pair of framing gates, positioning the thirdpair of framing gates on a second side of one of the first and secondpairs of carousels, and discharging the third pair of framing gates fromthe second side of the respective carousels for delivery to the framingstation. This methodology allows the random interchange of three pairsof framing gates at the framing station without interrupting the buildcycle time interval of the assembly line.

[0023] According to the present invention, the method can include thesteps of providing a fourth pair of framing gates, positioning thefourth pair of framing gates on opposite sides of the framing station,and randomly interchanging the pair of framing gates positioned at theframing station by selective rotation of the carousels and selectivesliding movement of the framing gates between the framing station andthe carousels. This methodology allows the random interchange of fourpairs of framing gates at the framing station without interrupting thebuild cycle time interval of the assembly line.

[0024] Other objects, advantages and applications of the presentinvention will become apparent to those skilled in the art when thefollowing description of the best mode contemplated for practicing theinvention is read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The description herein makes reference to the accompanyingdrawings wherein like reference numerals refer to like parts throughoutthe several views, and wherein:

[0026]FIG. 1 is a perspective view of a body framing system according tothe present invention;

[0027]FIG. 2 is a schematic plan view of the body framing system;

[0028]FIG. 3 is a perspective view of a portion of the framing system;

[0029]FIG. 4 is a plan view of a carousel used in the framing system;

[0030]FIG. 5 is a schematic plan view of the carousel of FIG. 4;

[0031]FIG. 6 is a plan view of a carousel base and linear trackstructure used in the framing system according to the present invention;

[0032]FIG. 7 is a perspective view of the linear track structure;

[0033]FIG. 8 is a schematic cross sectional view of the track structure;

[0034]FIG. 9 is a perspective view of the carousel base structure;

[0035]FIG. 10 is a perspective view of a carousel section;

[0036]FIG. 11 is a schematic view of a cushion system to facilitateturning of the carousel;

[0037]FIGS. 12 and 13 are detailed views of the cushion system;

[0038]FIGS. 14 and 15 are end and perspective views respectively of alatch release mechanism used in the framing system according to thepresent invention;

[0039]FIGS. 16, 17 and 18 are further detailed views of the latchrelease mechanism;

[0040]FIGS. 19 and 20 are elevational and perspective views respectivelyof a trolley assembly used in the framing system according to thepresent invention;

[0041]FIG. 21 is a perspective view of a lift mechanism forming a partof the trolley assembly;

[0042]FIGS. 22 and 23 are perspective views of a trolley forming a partof the trolley assembly;

[0043]FIGS. 24, 25 and 26 are elevational, cross-sectional andperspective views, respectively, of a caterpillar bearing used in theframing system according to the present invention;

[0044]FIG. 27 is a schematic view of a carousel assembly;

[0045]FIG. 28 is a schematic view illustrating the manner in which theframing system according to the present invention operates tointerchange pairs of framing gates at the framing station;

[0046]FIG. 29 is a simplified schematic view of a carousel according tothe present invention having two sides; and

[0047]FIG. 30 is a simplified schematic view of a carousel according tothe present invention having four sides.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0048] As seen in FIG. 1, the framing system of the present invention isintended for use with a vehicle assembly line 10 in which looselypreassembled vehicle bodies 12 are moved incrementally along theassembly line from station to station, successively loosely preassembledvehicle bodies arrive at a framing station 14 along the assembly line atpredetermined build cycle time intervals, and each loosely preassembledvehicle body arriving at the framing station is welded to form a rigidvehicle body. The framing system, broadly considered, (FIGS. 1, 2 and 5)includes framing station 14, a plurality of carousel assemblies 18, 20,22 and 24; a plurality of linear track structures 26, 28, 30 and 32; aplurality of trolley assemblies 34, 36, 38 and 40; and a plurality offraming gate pairs 42/43, 44/45, 46/47, and 48/49.

[0049] Framing station 14 includes a first framing station assembly 50positioned on one side of the assembly line 10 and a second framingstation assembly 52 positioned on the opposite side of the assembly line10 and constituting a mirror image of framing station assembly 50. Withreference to FIG. 3, framing station assembly 50 includes a basestructure 54 and a pair of axially spaced pillars 56, 58 mounted ontracks 60 and moved by a motor mechanism 62, in unison, between aretracted outboard position to facilitate loading of the framing gatesand an inboard position, seen in FIG. 3, proximate the assembly line 10where framing gates carried by the pillars can clampingly engage aloosely preassembled body 12 prior to the welding operation.

[0050] Framing station assembly 50 further includes a track structure 64positioned between the pillars 56 and 58 and defining a top rail 66, anda plurality of welding guns 68 (FIG. 1) positioned on or proximate thebase 54 and arranged to extend in known manner through suitable openingsin the framing gates to access the loosely preassembled vehicle bodies12 clampingly engaged by the framing gates to perform the desiredwelding operations on the clamped vehicle bodies. Further details of aframing station suitable for use as a part of the invention framingsystem are described in U.S. Pat. No. 6,173,881 assigned to the assigneeof the present invention.

[0051] The structure and operation of the framing system will now bedescribed with specific reference to carousel assembly 18, linear trackstructure 26, and trolley assembly 34. In overview it will be understoodthat carousel assembly 18, linear track structure 26, and trolleyassembly 34 coact to move framing gates upstream along assembly line 10to framing station assembly 50 from a location on one side of theassembly line; carousel assembly 20, linear track structure 28 andtrolley assembly 36 coact to move framing gates upstream to framingstation assembly 52 from a location on the opposite side of assemblyline 10; carousel assembly 22, linear track structure 30, and trolleyassembly 38 coact to move framing gates downstream to framing stationassembly 50 from a location on the one side of assembly line 10; andcarousel assembly 24, linear track structure 32 and trolley assembly 40coact to move framing gates downstream to framing station assembly 52from a location on the opposite side of assembly line.

[0052] With reference to FIGS. 2, 3, 4, 10 and 11, carousel assembly 18includes a carousel body 70 having a triangular configurationconstituted by at least two sides or, as illustrated, three identicalcarousel sections 72 which are configured to be clustered and boltedtogether to form a three sided or triangulated carousel body. It shouldbe recognized that two sided configurations, similar to that shownschematically in FIG. 29, or four sided configurations, similar to thatshown schematically in FIG. 30, or more sides can be provided as desiredfor the particular assembly without departing from the presentinvention. Journals 76 positioned at the inner juncture of the clusteredand bolted carousel sections 72 are received on an upstanding pivot postor shaft 78 carried by a carousel base structure 80 to mount thecarousel body for rotation about the central axis of pivot shaft 78.

[0053] Carousel assembly 18 further includes an annular turn table 82underlying the carousel body, a servo motor 84 including a pinion gearor tire 86 driving the turntable, and a fixed annular support plate 88positioned on base 80 in underlying relation to turntable 82 anddefining an upper annular support surface 88 a. Carousel assembly 18further includes a plurality of circumferentially spaced air bagassemblies 90 (FIGS. 11, 12 and 13) positioned in downwardly openingcavities 82 a in the under face of turntable 82 in overlying relation tosupport surface 88 a of support plate 88. There can be two air bagsassemblies underlying each carousel section 72 for a total of 6circumferentially spaced air bag assemblies underlying the carouselbody. It will be seen that when pressurized air is delivered to the airbag assemblies 90 via conduits 92 connected to a suitable source ofpressurized air, pressurized air will inflate the diaphragm 90 a of eachair bag and the pressurized air will flow through apertures 90 b in thelower wall of the diaphragm and flow radially outwardly, as seen by thearrows in FIG. 12 to create an air film or cushion beneath the diaphragm90 a. This inflating action of the air bags has the effect of raisingthe carousel body 70 on the post 78 off of support surface 88 a with theupward movement of the carousel body permitted and defined by slidingmovement of annular bearings 76 on post 78, and has the further effectof creating an air film between the carousel body and the supportsurface 88 a so that the motor 84 via the pinion gear or tire 86 andturntable 82 can readily turn the carousel body to bring successivesides of the carousel body into proximity and alignment with assemblyline 10. Each carousel frame section 72 has a generally latticeconfiguration (FIG. 10) including a vertical rectangular main bodyportion 72 a, an upper track structure 72 b, a lower track structure 72c, and a connector structure 72 d. Main body 72 a can be formed forexample of a series of spaced vertical post members 72 e; upper trackstructure 72 b can be formed of a series of spaced horizontal postmembers 72 f supporting a pair of laterally spaced longitudinallyextending angle irons 72 g; and lower track structure 72 c can include aplurality of spaced horizontal post members 72 h supporting an aprontrack 72 i which in turn supports a roundbar guide rod 72 j. A pluralityof spaced saddle gussets 72 k interconnect the main body 72 a and lowertrack structure 72 c. Connector structure 72 d is configured to meetwith the connector structure 72 d of the remaining carousel sections injigsaw puzzle fashion to form the triangular configuration of thecarousel clustered about central post 78. Carousel assemblies 20, 22 and24 are identical to the described carousel assembly 18.

[0054] Referring now to FIGS. 29 and 30, the illustrated carouselassemblies 18 a, 18 b respectively are identical in operation andfunction to the previously described carousel assembly 18 with theexception of having two sides or carousel sections 72 a, and four sidesor carousel sections 72 b respectively for receiving and deliveringframing gates to the framing station assembly 50. It should berecognized that the carousel assembly can have at least two sidesaccording to the present invention, and can include three sides, or foursides, or more four sides, depending on the particular framing stationassembly to be supplied with framing gates, as well as otherconsiderations, such as available floor space and flexible changeoverrequirements for the assembly line.

[0055] Linear track structure 26 is arranged for coaction with carouselassembly 18 and specifically is arranged to deliver framing gates fromcarousel assembly 18 to framing station assembly 50. Track structure 26(FIGS. 3, 6, 7 and 8) includes a belt shuttle frame 91, a vertical guidetrack 93, a horizontal guide track 94, and a roundbar rail 96. Beltshuttle frame structure 91 has a generally tubular steel frameconstruction and defines an overall cage configuration. Vertical guidetrack 93 is supported on belt shuttle frame structure 91 in overlyingrelation to the belt shuttle frame structure and runs the full length ofthe track structure. Horizontal guide track 94 is supported on the beltshuttle frame structure 91 in a position above and laterally of verticalguide rail 93 and extends from a first end 96 a at a locationintermediate the track structure to a second end 96 b proximate theframing station assembly 50. Roundbar rail 96 is fixedly secured to theupper face of track 96 and is coextensive with the track, extending froma location 96 a intermediate the track structure to a location 96 bproximate framing station assembly 50. Track structure 32 is identicalto track structure 26; track structure 28 is a mirror image of trackstructure 26; and track structure 30 is identical to track structure 28.

[0056] Trolley assembly 34 (FIGS. 7, 19, 20, 22 and 23) includes atrolley 98, a lift mechanism 100, and a shuttle belt assembly 102.Trolley 98 is intended to move slidably along the track structure 26while conveying a framing gate from the carousel to the framing station.Trolley 98 includes a lower base member 104 and an upper dump member106. Base member 104 includes lower clamping plates 108 and furtherdefines a plurality of rollers 110 configured to rollably engageopposite side faces of vertical track 92 as the trolley moves along thetrack structure. Base 104 further includes rollers 112 adapted torollably engage the lower edge of guide rail 92 as the trolley movesalong the track structure. Dump member 106 defines an arcuatesemicircular cut out 106 a for coaction with roundbar rail 96 andfurther includes rollers 114 for coaction with lifter mechanism 102, andcam follower rollers 116 for rollable engagement with the upper face ofhorizontal guide track 94. Dump member 106 is pivotally mounted on basemember 104 by a pivot shaft 118 and includes a receiver section 106 bincluding a cut out 106 c and carrying spaced pilot plates 120 defininga notch or a slot 122 therebetween for receipt of a gate dog membercarried by a framing gate.

[0057] Lift mechanism 100 is intended to pivotally move dump member 106about the axis of pivot 118 between a raised position in which the notch122 can engage the gate dog on a framing gate and a lowered position inwhich the gate dog is released and the gate is free to move relative tothe trolley. Lift mechanism 100 (FIGS. 19, 20 and 21) includes a framestructure 124 (including a horizontal base plate portion 124 a, avertical plate portion 124 b and spaced vertical plate portions 124 c);a vertical slide plate 126 mounted for vertical sliding movement onvertical plate portion 124 b by linear bearings 128 and including at itsupper end a U-shaped receiver portion 126 a receiving the rollers 114 ofthe dump member 106 of the trolley; a toggle mechanism including a firstupper toggle link 130 pivotally connected at its upper end to slideplate 126 and a second lower toggle link 132 pivotally connected at itslower end to vertical plate portions 124 c, and an air cylinder 134including a cylinder 134 a pivotally mounted between plate portions 124c and a piston rod 134 b pivotally mounted at its free end to thepivotal connection at 136 between the lower end of the upper toggle link130 and the upper end of lower toggle link 132. It will be seen thatactuation of air cylinder 134 has the effect of opening and closing thetoggle movement and thereby sliding vertical slide bracket 126,including the upper receiver portion 126 a, up and down to thereby (byvirtue of the capture of rollers 114 in receiver portion 126 a) pivotthe dump member 106 of the trolley about the axis of pivot shaft 118 andmove the pilot plates 122 into and out of engagement with the framinggate dog.

[0058] Shuttle belt assembly 102 (FIGS. 3, 6, 7 and 19) includes apowered pulley 140 mounted between spaced plates 91 a proximate thedownstream end of belt shuttle frame structure 91; an idler pulley 142mounted between spaced plates 91 b proximate the upstream end of beltshuttle frame structure 91; a pair of toothed endless belts 144 arrangedin endless fashion around pulleys 140 and 142; and a servo motor 146drivingly connected to powered pulley 140 and operative to drive thepulley and thereby drive the toothed endless belts 144. Belts 144 arefixedly secured to the underface of trolley base member 104 usingclamping plates 108 whereby actuation of servo motor 146 has the effectof moving trolley 98 along track structure 26 from the downstream end ofthe structure to the upstream end of the structure. As the trolley movesalong the track structure, rollers 110 engage opposite side faces ofvertical guide rail 92 and rollers 112 engage the lower edge of guiderail 92 to guide the movement of the trolley along the track structure.Trolley assembly 40 is identical to trolley assembly 34; trolleyassembly 36 is a mirror image of trolley assembly 34; and trolleyassembly 38 is a mirror image of trolley assembly 40.

[0059] Framing gate 42 will now be described in detail. It will beunderstood that the remaining framing gates have a similar constructionbut will differ from each other with respect to tooling, clamps, etc.carried by the gate since the clamps and tooling will be peculiar to theparticular motor vehicle body style for which the gate is designed.Framing gate 42 (FIGS. 3, 11 and 14) has a generally rectangular latticeconfiguration and a generally tubular steel frame construction. Theupper edge of the gate includes a plurality of guide rollers 150 forrollably guiding in the angle irons 72 g of a respective upper track ofa respective carousel; a pair of axially spaced bearing structures 152on the lower edge of the gate rollably guiding on the roundbar guiderail 72 j of a respective lower track of a respective carousel; and agate dog 154 along the lower edge of the gate for coaction with thenotch 122 of the dump member of the respective trolley 98. Bearings 152can be of the “caterpillar” type capable of crawling along the rounbarguide rail 72 j and capable of jumping the gap between the roundbarguide rail 72 j and the roundbar guide rail 96 of the associated lineartrack structure as the gate is moved along the track structure by thetrolley. Bearings 152 can, for example, be of the type shown in FIGS.24, 25 and 26, available from Thompson Industries, Inc., as part numberRW-1 WA. Gate 42 further includes finger members 156 projectingdownwardly at the rear face of the gate in rearwardly spaced relation tothe main body structure 42 a of the gate. Fingers 156 facilitate theengagement of the gate with the pillars 56, 58 after arrival of the gateat the framing station in a manner more fully described in U.S. Pat. No.6,173,881 B1 assigned to the assignee of the present application.Specifically, the fingers 156 coact with the pillars 56 and 58 in themanner shown and described with reference to FIG. 13 of U.S. Pat. No.6,173,881 or in the manner shown and described with reference to FIG. 20of that patent. Gate 42 will be seen to define a plurality of mountingplates 158 positioned on the main body 42 a of the gate in selectedpositions and in various configurations with respect to the gate. Itwill be understood that these mounting plates are for use in mountingtooling and clamping components on the gate for use in clamping theloosely preassembled body at the framing station prior to the weldingoperation. It will be further understood that a pair of gates (42, 43,for example) would be used in clamping the loosely preassembled vehiclebody at the framing station from opposite sides of the assembly line andthat each pair of framing gates (42, 43; 44, 45; 46, 47; and 48, 49)would include mounting plates and tooling and clamping componentspeculiar to the body style corresponding to the respective pair offraming gates.

[0060] The invention framing system further includes a latching devicefor latching and unlatching a gate to the carousel and a latching devicefor latching and unlatching the carousel to the base structure. Forreasons of compactness and servicing, these two latching functions arecombined in a single combined latch assembly 160, seen in FIGS. 14-18.Combined latch assembly 160 includes a base structure 162 that isadapted to be fixedly secured to a carousel base structure 80 at alocation proximate a corner of the carousel base structure; a furtherbase structure 164 adapted to be fixedly secured to the carousel basestructure proximate base structure 162; a jib slide structure 166adapted to be fixedly secured to the carousel body proximate each cornerof the carousel body; a T-bar slide 168 slidably mounted in each jibslide and including spaced rollers 170 at the upper end of the slide; aplate slide 172 mounted for vertical sliding movement on the base plate162 and including spaced rollers 174 proximate an upper edge of theslide plate; an air cylinder 176 including a cylinder 178 mounted on apiggy back plate 180 with the free end of piston rod 182 pivotallymounted to a lower edge of base plate 162; an air cylinder 184 includinga cylinder 186 mounted on piggy back plate 180 and with the free end ofpiston rod 188 pivotally secured to the slide plate 172; an L-shapedlift bar or arm 190 fixedly secured at one end to slide plate 172 andterminating in a vertical tip portion 190 a; a finger 192 pivotallymounted on lift bar 190 proximate tip portion 190 a and including a hookshaped upper portion 192 a; and a pair of cam rollers 194 mounted onbase member 164 and slidably and cammingly engaging opposite edgesurfaces of finger 192. Latch assembly 160 is intended for selectivecoaction with a precision dog 196 provided on the rear face on eachframing gate and a locator block 198 provided at each corner of thecarousel body. In overview, rollers 174 are sized to coact with block198 to lock the carousel body to the carousel base structure and rollers170 are sized to coact with precision dog 196 to lock a framing gate toa respective side of the carousel body. Specifically, as the carouselbody is turned to bring one side of the carousel body into alignmentwith the assembly line, cylinder 176 is fired to move plate slide 172upwardly on base plate 162 (carrying the cylinder 186 with it inpiggyback fashion) to move rollers 174 into straddling relation with thelocator block 198 proximate the respective side of the carousel. Thisupward sliding movement of plate 172 has the effect of bringing the topedge 190 b of arm 190 into engagement with the lower end 168 a of T-barslide 168 without upwardly displacing the slide thereafter the cylinder186 is fired to move slide 172 further upwardly, while retaining lockingengagement between rollers 174 and precision block 198, to raise theT-bar slide 168 and disengage rollers 170 from precision dog 196 tounlatch the framing gate from the carousel body. As T-bar slide 168 ismoved upwardly by arm 190, cams 194 operate to move the hooked portion192 a of finger 192 into overlying relation with a peg 168 b on thelower end of slide 168. When cylinder 184 is thereafter fired tore-engage rollers 170 with precision dog 196 to re-establish a latchedconnection between the respective framing gate and the carousel body,rollers 170 are moved downwardly in a positive manner by the positivepulling action of hook portion 192 a on peg 168 b, rather than relyingon gravity to accomplish the latching movement of the slide 168.Following firing of cylinder 184 to positively move the rollers 170 intolatching engagement with the precision dog on the respective framinggate, the cylinder 176 can be fired to further lower slide 172 todisengage rollers 174 from locator 198 to unlatch the carousel body fromthe carousel base structure to allow turning movement of the carouselbody to bring a new framing gate into alignment with the assembly line.As plate slide 172 moves downwardly to disengage rollers 174 fromlocator block 198, cams 194 selectively engage the opposite edges offinger 192 to allow the finger to rotate outwardly and move downwardlyto the disengaged position seen in FIG. 16 preparatory to a newunlatching operation of a respective framing gate.

Operation

[0061] In the overall operation of the framing system of the invention,the four carousel assemblies 18, 20, 22 and 24 and the four linear trackstructures 26, 28, 30 and 32 coact to bring selected pairs of framinggates to the framing station for use in clamping the opposite sides of aloosely preassembled vehicle body preparatory to the welding operation.With particular reference to carousel assembly 18 and linear trackstructure 26, the carousel body can be selectively rotated to bring eachof the three sides of the carousel body into alignment with the assemblyline to deliver a framing gate to the track structure 26 for delivery tothe framing station 14 following each turning movement of the carousel.To facilitate the rotation of the carousel body, pressurized air isdelivered to air bags 90 to inflate the air bags and lift the carouselbody off of support surface 88 a while pressurized air flows through thediaphragm apertures 90 b to form a film of air between the diaphragms ofthe air bags and the support surface 88 a, thereafter motor 84 can beactuated to rotate the carousel body through 120° to bring successivesides of the carousel body into alignment with the assembly line. Notethat (FIGS. 6 and 10) the downstream end 94 a of track 94 is chamferedand that the ends 72 l of carousel lower track 72 c are complementarilychamfered so that as each side of the carousel body moves into alignmentwith the assembly line the respective chamfered end of the carousellower track structure moves into a nesting, parallel disposition withrespect to chamfered track end 94 c.

[0062] During the rotation of the carousel body between successivepositions, latch assembly 160 has been actuated in a manner such thatthe carousel body is free to turn relative to the carousel base and eachgate carried by the carousel body is fixed with respect to therespective side of the carousel body by engagement of rollers 170 withprecision dog 196. As a respective side of the carousel body carrying adesired framing gate arrives at a position in alignment with theassembly line, cylinder 176 is fired to latch the carousel body to thecarousel base structure, thereafter air cylinder 134 is actuated toraise slide plate 126 and pivot dump member 106 upwardly about the axisof pivot shaft 118 to move the dog 154 on the framing gate into groove122 on the receiver 106 b of the dump member, thereafter cylinder 184 isfired to disengage rollers 170 from precision dog 196 to unlatch theframing gate from the carousel body, thereafter the delivery ofpressurized air to the air bags 96 is discontinued to allow the carouselto settle back down onto the support surface 88 a, thereafter servomotor 146 is actuated to drive powered pulley 140 and power endlessbelts 144 and the endless belts in turn move trolley 98 along the trackstructure 26 to move the framing gate along the track structure to theframing station. Specifically, as the trolley and the captured framinggate move along the track structure toward the framing station, thecaterpillar bearings 152 on the lower edge of the framing gate crawlalong the roundbar 70 c, jump the gap between the roundbar 70 c and theroundbar 96, and continue crawling along the roundbar 96 until theframing gate arrives in the proximity of the framing station.

[0063] Meanwhile, the trolley pushes the framing gate along the trackstructure, and is guided on the vertical rail 92 by virtue of therollers 110 and the rollers 112, guided on the roundbar 72 j of thecarousel lower track structure by virtue of the sliding engagement ofthe arcuate groove 106 a with the roundbar 72 j, followed by slidingengagement of the arcuate groove 106 a on the round bar 96; and guidedon the lower track structure of the carousel body by virtue of therolling engagement of the rollers 116 on the track apron 72 i proximatethe roundbar followed by rolling engagement of the rollers 116 on thehorizontal guide plate 194 proximate the roundbar 196. The slidingmovement of the framing gate along the track structure is furtherfacilitated by the rolling engagement of the rollers 150 in the overheadangle irons 72 g of the carousel followed by rolling engagement of therollers 150 in overhead angle iron tracks 200 forming a continuation ofthe angle irons 72 g and extending to a location overlying the framingstation 14. As the gate approaches the framing station the pillars 56 an58 are in the retracted or outboard positions to allow passage of thegate in front of the pillars to position the gate on the pillars. As theleading edge of the gate reaches and traverses the first pillar 58, thefront caterpillar bearing 152 loses contact with rail 96 but the gatecontinues to be firmly guided during this brief transition time by thecontinued engagement of the trailing caterpillar bearing 152 on theroundbar 96, by the firm guidance of the overhead rollers 150 in theoverhead tracks 200, and by the firm guidance of the lower edge of thetrolley with the guide rail 92, the roundbar 96, and the horizontal rail94 proximate the roundbar 96. Once the leading edge of the gate hastraversed the pillar 58, the leading caterpillar bearing 152 engages theroundbar 164 and the movement of the framing gate continues until theleading edge of the framing gate encounters the second pillar 56 andmoves past the second pillar 56 to position the gate against bothpillars 56 and 58, at which time the framing gate is secured to thepillars in the matter described in U.S. Pat. No. 6,173,881, thereafterthe pillars carrying the captured framing gate are moved from theoutboard positions to the inboard positions to coact with the pillarsand the matching framing gate 43 on the opposite side of the assemblyline to firmly clamp a loosely preassembled vehicle body therebetweenpreparatory to the welding operation. As the pillars move forwardly tothe inboard positions, the framing gate is able to move with the pillarsby virtue of the passage of the overhead guide rollers 150 throughsuitable gaps 200 a provided in the overhead guide rails 200.

[0064] The framing gate 42 will remain mounted on the pillars 56, 58 forcoaction with the framing gate 43 carried by the pillars at the framingstation on the opposite side of the assembly line for as long as it isdesired to continue to build the same body style vehicle. Specifically,the pillars will be moved to an inboard position each time a vehiclebody arrives, thereafter the vehicle body will be clamped, thereafterthe vehicle body will be welded, thereafter the pillars will be movedoutwardly to the outboard positions until the arrival of the nextsuccessive loosely preassembled vehicle body at the framing station,thereafter the pillars will again be moved to the inboard positions andthe clamping and welding cycle repeated. This pattern will continue foras long as it is desired to continue to build the same body style.However, and in accordance with an important feature of the invention,the pair of framing gates 42, 43 required to build the specific bodystyles can be randomly and readily interchanged for any of the othersets of framing gate pairs (44, 45; 46, 47; 48, 49) without interruptingthe build cycle time of the assembly line.

[0065] That is, the combined rotary carousel and linear trackarrangement of the invention allows the interchange of framing gatescorresponding to four different body styles at the framing stationwithout interrupting the build cycle time of the assembly line so thatany mix of the four body styles can be provided at any time and duringany time period without any penalty in the number of vehicles producedby the assembly line during that time period. For example, and withreference to FIG. 28, with framing gate pair 42 and 43 positioned onopposite sides of the framing station 14; framing gate pair 44 and 45positioned respectively on first sides of the carousels 30 and 32proximate the assembly line; framing gate pair 46 and 47 positionedrespectively on second sides of carousels 30 and 32 removed from theassembly line; and framing gate pair 48 and 49 positioned respectivelyon first sides of carousels 26 and 28 removed from the assembly line,framing gates 42 and 43 can be randomly interchanged with any of theother pairs of framing gates within the build cycle time of the assemblyline. Assuming a build cycle time for the assembly line of 45 seconds,the described arrangement, with the gates positioned as described,allows any of the gate pairs to be interchanged with the gate pair 42,43 in less than 45 seconds. Specifically, it will be seen that anexchange can be accomplished by simple linear movements of gate pairsalong the linear track structures or by a combination of linearmovements of gate pairs along the linear track structures and rotarymovement of selected carousels.

[0066] In the scenario where only linear movement of the involved gatepairs is required (as for example replacing gate pair 42, 43 with gatepair 44, 45 simply by moving gate pair 42, 43 linearly downstream fromthe framing station to the vacant side of carousels 26, 28 and movinggate pair 44, 45 downstream to the framing station) the exchange timeconsists of only approximately 3 seconds to perform the various latchingand unlatching operations, and 5 seconds of linear sliding time for atotal of approximately 8 seconds, well within the 45 second build cycletime target.

[0067] In the more complicated scenario where it is desired to exchangegate pairs 42 and 43 with gate pairs 46 and 47, carousels 30 and 32 arerotated counterclockwise through 120° to bring gates 46 and 47 intoproximity with the assembly line while gate pair 42 and 43 is sliddownstream to the vacant sides of carousels 26 and 28, thereafter gates46 and 47 are slid downstream to opposite sides of the framing station.The total time for this operation being approximately 16 seconds torotate the carousels, 5 seconds to perform the sliding operations, andapproximately 3 seconds to perform the various latching operations for atotal time of 26 seconds, again well within the 45 second build cycletime target.

[0068] To exchange gates 48 and 49 for gates 42 and 43, carousels 30/32are rotated 120° clockwise to bring the vacant side of these carouselsinto alignment with the assembly line while carousels 26 and 28 arerotated 120° counterclockwise to bring gates 48 and 49 into proximity tothe assembly line, thereafter gates 42/43 are slid upstream to occupythe vacant side of carousels 30/32 while gates 48/49 are slid upstreamto move gates 48 and 49 to the opposite sides of the framing station.The total time for this exchange again being approximately 26 seconds,including 16 seconds to rotate the carousels, 5 seconds to perform thesliding operations, and approximately 3 seconds to perform the variouslatching operations, again well within the 45 second build cycle timetarget.

[0069] Similar analysis of the various frame interchange scenarios willestablish that the combination of rotary and sliding movement allows therandom interchange of four pairs of framing gates to allow the randomproduction of any mix of four body styles on the assembly line withoutinterrupting the build cycle time of the assembly line so that theassembly line can turn out the same number of vehicles irrespective ofthe mix amongst the four body styles. It will also be apparent that thearrangement allows the production of five body styles on the sameassembly line, but, in this case, there are certain interchangescenarios where it would not be possible to interchange the pair ofgates positioned at the framing station with another pair of gatespositioned on one of the carousels within the build cycle time, eventhough certain interchanges would be possible within the build cycletime.

[0070] The invention apparatus and method will be seen to provide therandom interchange of more than three pairs of side framing gates at aframing station while maintaining a predetermined build cycle timeinterval of the assembly line to allow any random mix of, for example,four body styles on a single assembly line without compromising theability of the assembly line, to maintain operation at the predeterminedbuild cycle time interval. Further, the apparatus and method accordingto the present invention, by virtue of its compact packaging, allows therandom interchange to be performed in the context of the physicalfloorplan constraints of a typical motor vehicle assembly plant buildingand specifically allows the system to be installed within the typically50′ wide bays dictated by the structural columns of the building.

[0071] While the invention has been described in connection with what ispresently considered to be the most practical and preferred embodiment,it is to be understood that the invention is not to be limited to thedisclosed embodiments but, on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims, which scope is to be accorded the broadestinterpretation so as to encompass all such modifications and equivalentstructures as is permitted under the law.

What is claimed is:
 1. A body framing system for use with a vehicleassembly line in which loosely pre-assembled vehicle bodies are movedincrementally along a single assembly line from station to station,successive loosely pre-assembled vehicle bodies arrive at a framingstation along the assembly line at predetermined build cycle timeintervals, and each loosely pre-assembled vehicle body arriving at theframing station is welded to form a rigid vehicle body, the body framingsystem including: the framing station; a plurality of more than threepairs of opposed side framing gates for positioning at opposite sides ofthe framing station for use in welding a respective plurality of morethan three vehicle body styles allowing random production of theplurality of more than three vehicle body styles on the single assemblyline; and a transfer apparatus assembly operative for randomlyexchanging any of the plurality of pairs of side framing gatespositioned at the framing station with any other of the plurality ofpairs of side framing gates within the predetermined build cycle timeinterval to allow the random production interchange of the more thanthree vehicle body styles on the single assembly line while maintainingthe predetermined build cycle time interval.
 2. The body framing systemof claim 1, wherein the transfer apparatus assembly includes a rotarytransfer apparatus coacting with a linear transfer apparatus.
 3. Thebody framing system of claim 2, wherein the rotary transfer apparatusdelivers framing gates to the linear transfer apparatus for delivery tothe framing station.
 4. The body framing system of claim 3, wherein therotary transfer apparatus includes first and second carousels positionedon opposite sides of the assembly line upstream of the framing stationand third and fourth carousels positioned on opposite sides of theproduction line downstream of the framing station.
 5. The body framingsystem of claim 4, wherein the linear transfer apparatus includes afirst linear track system extending from the first carousel to a firstside of the framing station, a second linear track structure extendingfrom the second carousel to a second, opposite side of the framingstation, a third linear track structure extending from the thirdcarousel to the first side of the framing station, and a fourth lineartrack structure extending from the fourth carousel to the second side ofthe framing station.
 6. The body framing system of claim 5, wherein eachcarousel has a polygonal configuration including at least two sides,each side capable of receiving a framing gate.
 7. The body framingsystem of claim 6, wherein the plurality of more than three pairs ofopposed side framing gates includes four pairs of framing gates, andeach carousel has three sides, wherein with the first pair of framinggates positionable on opposite sides of the framing station, the secondpair of framing gates positionable on respective first sides of thefirst and second carousels, the third pair of framing gates positionableon respective second sides of the first and second carousels, and thefourth pair of framing gates positionable on respective first sides ofthe third and fourth carousels, all of the pairs of framing gatescapable of being randomly interchanged by at least one of linear gatemovements along the linear track structures and a combination of rotarymovements of the carousels and linear gate movements along the lineartrack structures.
 8. The body framing system of claim 5 furthercomprising: a base structure; a first pair of spaced pillars mounted onthe base structure on the first side of the framing station; and asecond pair of spaced pillars mounted on the base structure on thesecond side of the framing station, the first and second pairs ofpillars moveable on the base structure between outboard positions spacedoutwardly from the assembly line and inboard positions proximate theassembly line, the first pair of pillars in its outboard positionlinearly aligned with the first and third linear track structures, andthe second pair of pillars in its outboard position linearly alignedwith the second and fourth linear track structures, wherein the framinggates are deliverable to the respective pillar pairs along therespective linear track structures with the pillar pairs in the outboardpositions, thereafter the pillar pairs movable to the inboard positionsto position the framing gates proximate the assembly line for clampinglyengaging loosely preassembled vehicle bodies preparatory to weldingoperations.
 9. A carousel for use in delivering framing gates to aframing station on a vehicle body assembly line, the carouselcomprising: a base structure positioned proximate the assembly line andincluding a support surface and a central pivot shaft upstanding fromthe support surface; a carousel body supported on the support surface,mounted on the pivot shaft for rotary movement about the axis of theshaft, and defining a plurality of sides, each side adapted to receive aframing gate; means operative for generating an air cushion between thesupport surface and an underface of the carousel body to lift thecarousel body off of the support surface; and means operative forapplying a turning force to the lifted body to rotate the body about thecentral axis to bring successive sides of the body into a positionproximate the assembly line.
 10. The carousel of claim 9, wherein theair cushion generating means further comprises a plurality of air bagspositioned on the underface of the carousel body and each air bagincluding a plurality of apertures in confronting relation to thesupport surface allowing pressurized air delivered to the air bags toinflate the bags to raise the carousel body off of the support surfaceand air escaping from the air bags through the apertures to generate anair cushion between the air bags and the support surface.
 11. Thecarousel of claim 10, wherein the air bags are positioned incircumferentially spaced relation about the central axis of the pivotshaft.
 12. The carousel of claim 10 intended for use with a linear trackstructure having one end positioned proximate the framing station and afree end, and further comprising: each side of the carousel bodyincluding a carousel track structure for supporting a respective framinggate and configured to be aligned with the free end of the linear trackstructure as the respective side of the carousel body is moved into aposition proximate the assembly line allowing the framing gate to beslid off the carousel track structure and onto the linear trackstructure for delivery to the framing station.
 13. A transfer apparatusfor use in delivering framing gates to a framing station on a vehiclebody assembly line, the transfer apparatus comprising: a linear trackstructure having one end positioned proximate the framing station and afree end; a carousel positioned proximate the assembly line, defining aplurality of sides each adapted to receive a framing gate, and mountedfor rotation about a central axis to bring successive sides of thecarousel into a position proximate the free end of the track structureand in linear alignment with the track structure; and a transfer deviceoperative to move a gate positioned on a side of the carousel inalignment with the track structure from the carousel side, onto thetrack structure, and along the track structure to the framing station.14. The transfer apparatus of claim 13 further comprising a trolleyoperative to engage a gate and move the gate along the track structureto the framing station.
 15. The transfer apparatus of claim 14, whereineach side of the carousel includes a carousel track structure forsupporting a framing gate positioned on the respective side of thecarousel and configured to be aligned with the free end of the lineartrack structure as the respective side of the carousel is moved into aposition proximate the free end of the linear track structure.
 16. Thetransfer apparatus of claim 15 further comprising: a first latch devicefor latching a framing gate to a respective side of the carousel; a basestructure supporting the carousel; a second latch device for latchingthe carousel to the base structure; and a latch control device operativein response to arrival of a carousel side at a position proximate thefree end of the linear track structure to actuate the second latchdevice to latch the carousel to the base structure and release the firstlatch device to release the framing gate from the carousel and allow thetrolley to move the released framing gate along the linear trackstructure to the framing station.
 17. The transfer apparatus of claim 16further comprising: a third latch device to latch the trolley to aframing gate, the third latch device actuated prior to release of thefirst latch device and following engagement of the second latch device,and wherein the first latch device is released following engagement ofthe third latch device to allow the trolley to move the released framinggate to the framing station.
 18. The transfer apparatus of claim 17further comprising: the base structure defining a support surface;cushion means operative to generate an air cushion between the supportsurface and an underface of the carousel to lift the carousel off of thesupport surface; and turning means operative to apply a turning force tothe lifted carousel to rotate the carousel about the central axis tobring successive sides of the carousel into position proximate the freeend of the track structure and in linear alignment with the trackstructure.
 19. The transfer apparatus of claim 18, wherein the secondlatch device is released following actuation of the cushion means,thereafter the turning means is actuated to bring a respective side ofthe carousel carrying a respective framing gate into alignment with thelinear track structure, thereafter the second linear latch device isactuated to latch the carousel to the base structure, thereafter thethird latch device is actuated to latch the trolley to the respectiveframing gate, thereafter the first latch device is released to releasethe respective framing gate from the carousel, and thereafter thetrolley is actuated to move the respective framing gate to the framingstation.
 20. The transfer apparatus of claim 19, wherein the cushionmeans is deactivated to lower the carousel back down to the supportsurface prior to actuation of the trolley to move the respective framinggate to the framing station.
 21. A method of moving pairs of framinggates to a framing station on a motor vehicle assembly line whereloosely preassembled vehicle bodies are clamped by the framing gatepairs while the bodies are welded to form a rigid vehicle body, themethod comprising the steps of: providing a pair of carousels eachhaving a plurality of substantially flat sides; positioning thecarousels along and on opposite sides of the assembly line in spacedrelation to the framing station; mounting the carousels for rotation tobring successive sides of the carousel into a discharge positionproximate and substantially parallel to the assembly line; positioning apair of framing gates on one side of the respective pair of carousels;rotating the carousels to bring the one carousel sides into thedischarge position; discharging the framing gates from the carousels;and sliding the framing gates along the assembly line to opposite sidesof the framing station.
 22. The method of claim 21 further comprisingthe step of: providing linear track structures extending from eachcarousel to the framing station; and wherein the sliding step of thedischarged framing gates along the assembly line to the framing stationincludes sliding the discharged framing gates along the linear trackstructures to the framing station.
 23. The method of claim 21, whereinthe rotating step of the carousels further comprises: generating an aircushion between an underface of the carousels and a support surface tolift the carousels off of the support surface; and thereafter applying aturning force to the lifted carousels.
 24. The method of claim 21,wherein the pair of carousels includes a first pair of carouselspositioned upstream on the assembly line from the framing station, andthe pair of framing gates includes a first pair of framing gates, andwherein the sliding step of the discharged framing gates along theassembly line to opposite sides of the framing station includes slidingthe framing gates downstream to the framing station, and furthercomprising the steps of: providing a second pair of carousels eachhaving a plurality of substantially flat sides; positioning the secondpair of carousels along and on opposite sides on the assembly linedownstream of the framing station; mounting the second pair of carouselsfor rotation to bring successive sides of the second pair of carouselsinto a discharge position proximate and substantially parallel to theassembly line; positioning a second pair of framing gates on one side ofthe respective second pair of carousels; rotating the second pair ofcarousels to bring the one sides of the second pair of carousels intothe discharge position; discharging the second pair of framing gatesfrom the second pair of carousels; and sliding the discharged secondpair of framing gates upstream to the framing station.
 25. The method ofclaim 24 further comprising the steps of: providing a third pair offraming gates; positioning the third pair of framing gates on a secondside of one of said first and second pairs of carousel; and dischargingthe third pair of framing gates from the second side of the respectivecarousels for delivery to the framing station.
 26. The method of claim25 further comprising the steps of: providing a fourth pair of framinggates; positioning the fourth pair of framing gates on opposite sides ofthe framing station; randomly interchanging the pair of framing gatespositioned at the framing station by selective rotation of thecarousels; and selective sliding movement of the framing gates betweenthe framing station and the carousels.